The U.S. Pat. to A. Chan et al, No. 4,841,560, and the U.S. Pat. to D. Heins et al, No. 5,528,660, assigned to the assignee of the present application and the disclosures of which are herein incorporated, describe line-conditioning devices that allow a single field technician or craftsperson to test a subscriber line without requiring participation by another technician at the far end of the line of interest (in the central office). For this purpose, such line-conditioning devices are installable in telephone system facilities (central offices) of a network, and are configured to be remotedly called or accessed `directly` by a craftsperson for the purpose of performing prescribed line-conditioning operations that are observable by the craftsperson's test set. Such a line-conditioning device is typically referred to as a direct access test unit or DATU.
More particularly, as diagrammatically illustrated in FIG. 1, a typical telephone network facility such as a central office 12 includes a central office switch 14, central office test devices 16, and a direct access test unit (DATU) 18. The central office test devices 16 are capable of providing an interface with various operational support systems of a data center 20, such as a service vehicle dispatch, outside plant record database, automated testing systems, and electronic network schematics.
The line-conditioning device (DATU) 18 provides the craftsperson with the ability to interactively apply test signals to a telephone line under test, and thereby selectively conduct a number of tests of a line under test (LUT), by invoking specified key combinations (sequences) from the craftsperson's telephone test set 22, which cause the transmission of tone signals (dual tone multi-frequency (DTMF) signals) to which the DATU is programmed to respond. Communications from a respective DATU to the craftsperson's test set are effected by means of synthesized voice messages sourced from the DATU, which are then audibly or visually presented to the craftsperson, depending upon the type of communications device being employed.
In order to enable the telephone service provider to monitor DATU usage, each DATU includes a set of usage parameter registers or counters that keep a record of every access by a test set. To monitor DATU usage, it has been conventional practice for network personnel to access a respective DATU within a bank of such circuits (which may literally involve hundreds of DATUs) by manually keying in tone signal-formatted messages using essentially the same procedure employed by a field technician to access a DATU for testing test a line. Since response messages produced by the DATU are formatted as synthesized voice reply messages, it is necessary for the individual accessing the DATU to listen to the reply message and manually record its contents, so that they may be entered into a spreadsheet database for subsequent analysis. Once the contents of the usage registers have been read, they are cleared. To access another DATU, the operator must then repeat the procedure. Because conventional usage access to each DATU is manually controlled, it is subject to user errors, is labor-intensive and is extremely time consuming. (Indeed, it is not uncommon for system personnel to spend on the order of four hundred hours or more per month calling into all the DATUs of a system).